Given below are four statements with reference to a catalyst. Choose the incorrect statement(s)
(A) A catalyst lowers the potential energy barrier, thus decreasing the activation energy.
(B) A catalyst lowers the Gibbs energy (ΔG) of the reaction.
(C) A small amount of catalyst converts a large amount of reactants into products.
(D) A catalyst can catalyze non-spontaneous reactions also.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (B) and (D) only
A catalyst provides an alternative path of lower activation energy. It is not used up, so a little of it can convert a large amount of reactant. It changes only the speed of a reaction, not its energetics: the energies of reactants and products, and so \( \Delta G \), stay the same.
(A) A catalyst lowers the potential energy barrier, thus decreasing the activation energy. — Correct. This is how a catalyst speeds up a reaction; by the Arrhenius equation, a lower \( E_a \) means a larger rate constant.
(B) A catalyst lowers the Gibbs energy (ΔG) of the reaction. — Incorrect. \( \Delta G \) depends only on the initial and final states, which the catalyst does not change.
(C) A small amount of catalyst converts a large amount of reactants into products. — Correct. The catalyst is given back unchanged at the end of each cycle and is used again.
(D) A catalyst can catalyze non-spontaneous reactions also. — Incorrect. A catalyst speeds up only reactions that are already spontaneous (\( \Delta G \lt 0 \)); it cannot make a non-spontaneous reaction go.
NCERT (2026-27 edition):
Effect of Catalyst – …
